锂离子电池三维网状结构硅薄膜负极材料的制备及其电化学性能

Preparation and electrochemical performance of 3D net structure silicon film anode in lithium-ion batteries

采用磁控溅射方法,以泡沫镍为导电基底,制备锂离子电池三维网状结构硅薄膜负极材料,并研究其电化学性能.结果显示,当硅薄膜的厚度为200 nm时,三维网状结构硅薄膜负极材料表现出良好的循环性能和倍率性能,以800 mA/g的电流充放电时,首次放电容量高达4060mAh/g,循环300周后容量保持在1704 mAh/g;充放电电流为4200 mA/g(1 C)时,首次放电容量为2940 mAh/g,循环300周后容量为1472 mAh/g;当充放电电流增大到21 A/g(5 C)时,放电容量仍高达1294 mAh/g.增加硅薄膜的厚度到600 nm,虽然其循环性能有所下降,但仍然保持优良的倍率性能.与平板硅薄膜材料相比,三维网状结构硅薄膜材料有效地缓解了硅在充放电过程中的体积变化,从而具有优异的电化学性能.

The 3D net structure silicon film anodes were prepared by magnetron sputtering method on a foam nickel substrate. Excellent electrochemical performances of these 3D net structure silicon film anodes are demonstrated. When the thickness of silicon film is 200 nm, the discharge capacity is 4060 mAh/g in the first cycle, and it retains 1704 mAh/g after 300 cycles at a charge/discharge current of 800 mA/g. Even the current is increased to 4200 mA/g（1 C）, the discharge capacity is still as high as 2940 mAh/g in the first cycle, and retains 1472 mAh/g after 300 cycles. When the thickness of silicon film is increased from 200 to 600 nm, the cycle performances of this 3D net structure silicon film anode decline in a certain degree, while it still maintains a better cycleability and rate capability than the panel silicon film with the same thickness. The improved electrochemical performances are attributed to that the 3D net structure can obviously restrain the volume change of silicon material during the insertion/extraction processes of lithium ion.